Feed collet and method of making the same



C. J. FANCHER AND R. A. JOHNSON.

FEED COLLET AND METHOD OF MAKING THE SAME..

APPLICATION FILED FEB.13. 1920. RENEWED JAN.3,1921.

Patented 0@1.31,1922.

WITNESS:

A TTORNE Y.

' and Ronnn'r A. J oHNsoN, both citizens of the Patented ct. 31, 1922.

STATES PATENT OFFICE.

CHARLES J. FANCHER AND ROBERT A, JOHNSON, OF WINDSOR, VERMONT, ASSIGNOBS TO THE NATIONAL ACME COMPANY,

OHIO.

OF CLEVELAND, OHIO, A CORPORATION OF FEED COLLET AND METHOD OF MAKING THE SAME.

Application filed February 13, 1920, Serial No. 358,501 Renewed January 3, 1921. Serial No. 434,841.

0 all whom it may concern:

Be it known that we. CHARLES J. FANGHER United States of America, and residents of Windsor, in the county of Windsor and State of Vermont, have invented a new and useful Feed Collet and Method of Making the Same, of which the following is a specification. 4

Our invention relates to improvements in collets used in automatic and hand-operated screw-machines, bar-forming machines, and the like, for feeding the stock, and consists of a blank of special formation, which is preferably stamped out of pressed-steel, rolled up and either butt-welded at the joint, or otherwise secured at said joint as by means of a soft steel ring, or both butt-welded and otherwise secured as by thering, the device thus constructed then being formed to give the required shape to the fingers. and adapt them to the size and shape of the work for which they are intended, turned and screw-threaded, and finally spring tempered and polished, all ashereinafter set forth.

Heretofore collets of the character de scribed or for the purpose set forth above have been made out of solid stock which has to be bored and slotted. -Collets constructed in this manner are difficult and expensive to make, and not so strongand durable as our collets. The primary object of our invention is, therefore, to produce a feed collet of the kind set forth which is both simple and comparatively inexpensive in construction,'while at the same time being strong, durable, highly efficient, and capable of performing in a satisfactory manner the functions required of such a feeding device.

, In the manufacture of feed collets drilled or bored from a solid stock or bar it has been necessary when the collet was to be used with a square or hexagon or oval-shaped piece of stock to provide the ends of the fingers with bushings or thickened portions, usually called pads, so as to conform to the shape of the stock to be fed. This is not only difiicult,-but is an expensive operation and frequently results in the breakage of the collet in use for the reason that the formation of these pads or thickened portions provided a shoulder on the inside of the collet against which the end of a new bar of stock, being fed into the collet, strikes and thus frequently breaks ofl one or more of the fingers.

In addition, it has not been heretofore practicable in a feed collet of this kind to .form the fingers of tapered form.

angle-formation was a material drawback in the hardening of the collet. The drilling of these holes at the bases of the slots necessarily took awaya portion of the metal at the base of the fingers and consequently left the neck at this point narrower than the free ends of the fingers, so that the fingers were weaker at this point than at any other point. Consequently the fingers frequently broke oif at this point Moreover, the drilling of a collet from a'- solid bar left on the inside thereof score marks or grooves, which materially weakened the walls of the fingers, and furthermore it was difficult in practice to so drill a bar that the walls andfingers would be uniform; consequently one finger would be thinner than another, thus resulting in a weak collet. Detachable collets of drilled form have been the only ones, so far as we are aware, that have evef been made or used prior to the present improvement.

In our collet the fingers may not only be tapered so that the bases thereof are of increased width compared with the front ends thereof, but no transversely drilled holes are necessary, and in which as the fingers are pressed toward the center or axis of the collet they may be formed to the desired shape of the stock to be fed as hexagonal, oval, square or otherwise, without the formation of pads or bushings on the interior thereof, and consequently without the formation of any abrupt shoulders for the stock to strike against;

Moreover, since the collet is formed from a fiat sheet metal blank, which has been pressed between rollers it follows that the ing of the interior of the collet to weaken it and consequently, the collet being uni form, it is more effectively tempered or hardened than is the case where the walls are of different thicknesses.

Other objects and advantages will appear in the course of the following description.

We attain the objects and secure the advantages of our invention by the means illustrated in the accompanying drawings, in which- I Figure 1 is a plan of a blank form from which a collet that is a practical embodiment of our invention is made; F i 2, an end elevation of a feed collet ma e from said blank form; Fig. 3, a side elevation of said collet, and, Fig. 4, a central, longitudinal section through a collet whichhas a ring binder incorporated therewith.

Similar reference numerals designate similar parts throughout the several views.

' This feed collet may be made with two or more resilient gripping fingers, as desired, three being shown in the example herein presented.

The collet is made from a blank struck from or stamped out of a piece of sheetsteel, as shown in the first view. This blank consists of a rectangular body part .1, and three finger pieces 2 that extend or project from one of the longer edges of said body part. Each finger piece 2 is generally wedge-shaped or tapered except at the outer terminal where the lateral edges of such finger piece are parallel as represented at 3. At the place of junction of each tapered edge of each finger piece 2 with the body part 1 there is a clearance between such edge and the next adjacent tapered part, or between such edge and the adjacent end of said body part, as the case may be. This clearance, represented at 4, is for a purpose which will presently appear.

The blank is bent or rolled and formed into the shape shown in the other views, with the end edges of the body part 1 forming a butt joint at 5, the body part 1 has now become a hollow cylindrical body 6, and the finger pieces 2 have now become tapered fingers 7. This tapered formation of the fingers. since they are of increased width at the se thereof. as compared with the free p thereof. gives greater strength and reslliency to the fingers, and in practice it has been demonstrated by aldng series of tests h t the fingers made in this way do not break off at the bases as has frequently occurred with the colle s made by drilling a so id bar of stock in which the fingers are not tapered, and in which transverse holes have been drilled at the bases of the fingers, thus making the necks thereof of less widt thanthe free ends of the fingers. The ion 5 1n the body 6 is completed by butt-welding the contiguous edges of the material at that place, in the Fig. 3 construction, and the corresponding joint may be completed in a similar manner and by similar means, in the Fig. 4 construction. Whether or not the latter construction be butt-Welded a steel ring or'ring binder 8 is forced on over the body 6 to hold the rolled elements in place, or to assist in so doing in the event the buttwelding also be employed. The ring binder 8 is located adjacent to the roots of the fingers 7, and covers about one-half of the exterior surface of the body or blank 6. The body or blank 6 is turned down or otherwise formed on the outside to an extent sufliclent to effect the formation of a shoulder between contiguous parts of said finger and the roots of the fingers 7.

The body or blank 6 is turned down or otherwise formed to form an exterior shoulder 9 about midway between the outer and inner ends of said body, orthe exposed end of the ring binder 8 may serve in place of such shoulder, and said body is exteriorly screw-threaded between said shoulder or said end of said binder and'the outer end of the body, as represented at 10. This screw-threaded part of the collet affords means for attaching the collet to the operating member therefor as the feed tube or spindle or member in the machine in which the collet is used while the shoulder acts as a stop to position the collet relatively to the feed member.

The fingers 7 are separated from each other by slots 11, the side edges of each of which are approximately parallel with each other, due to the clearance at the junctions between the body part 1 and the finger pieces 2, to which reference has hereinbefore been made. It is also due to this clearance .at the ends of the body part 1, or between such ends and the outermost side edges of the finger pie"es 2, that. when the blank is rolled up and formed to shape, said edges form one of the slots 11 and form it of the same size and shape as are the other two slots 11.

When the blank is bent or rolled and formed to produce the collet, the paralleledged terminals 3 of the finger pieces 2 are bent or rolled and drawntogether into a hollow gripping portion or cylinder of less diameter than that of the body 6, the walls of which cylinder are broken, however, by the slots 11. At the same time the remaining portions of the finger pieces 2 are given a tapering configuration both exteriorly and interiorly. Thus it is seen that the fingers 7 have a conical cylindrical sectional shape or form. The opening or passage through the body 6 is large and cylindrical, the axial opening or passage through the fingers 7,

liich latter passage is, of course, a continuation of said first-named passage, tapers and grows smaller as the finger tips are approached, and the outer terminal portion of said last-named passage is substantially cylindrical and considerably smaller than the passage through said body, as stated above. It is the portions ofthe fingers 7 through which extends the small, cylindrical, axial passage, of which mention has just been made, that grip the stock. Inasmuch as the fingers 7 are resilient, they can feed or assist in feeding the stock, as well as grip the same. The stock-gripping parts of the fingers 7 are represented at 12, the inner walls of which are shown as substantially straight in the direction of their length and are therefore substantially parallel in the direction of their length regardless of the particular formation of the side edges 3,which may vary according to the size of the collet, thereby to insure a proper gripping surface on the work.

The collet is used and operates in a similar manner to collets constructed out of solid material and in the old way, the stock fed by our collet extending through the same just as is the case with the others.

The thickness of the material out of which the collet of the drawings is made is very much exaggerated in said drawings. In practice said materialis much thinner.

We have found'that butt-welding is sufficient as a rule to join and hold together the abutting edges of thef body part 1 when rolled up, so that the ring binder seldom if ever need be added, and furthermore,that the first method or means is cheaper than the ring and on that account to be preferred rather than the latterwhen either is to be used'alone.

Our type of feed collet is stronger than. the old type. due to the fact that it is made of sheet-steel, both surfaces of which have been subjected to the compressing action of the rolls in producing the sheet, so that the steel is more dense and by reason of this 1 form in some instances is laid-lengthwise of the 'sheet. The blank for our collet is in some instances stamped out with the grain runpressure, the walls of the metal are of unithickness throughout; and the grain ning lengthwise of the finge r pieces, consequently when they are formed up the inner surface isas strong as the outer surface. This is not. the case with a drilled-collet, inasmuch as the operation of drilling the solid stock weakens the inner surface produced by said operation, and thisis' the surface which is subjected to the most strain when the collet is in use.

The fingers of different collets will vary somewhat in the manner of their constriction and in shape, so as to adapt them to fit various sizes of rods or bars of stock, and to different shapes in cross section of such bars or rods, such as, round, square, hexagonal, etc. r

In other words, the fingers-are pressed toward the center or axis. of the collet and rotate with such stock bar.

to the shape desired, that is to say, if the collet is to be used with a hexagonal or oval or square piece, then the ends of the fingers are pressed into this shape, thustdoing away with the necessity of forming pads or bushings on the interior of the fingers, and consequently doing away with the formation of any abruptshoulder on the interior of the collet.

.From the foregoing it will be observed that the gist of the present improvement is the provision of a feed collet adapted for detachable connection with the feed member as the end of a rotary stock bar feed tube of a machine, such as a metal working machine, so that the collet will rotate with such tube and with the stock bar andso that it will successively grip a bar of stock in such machine as it is intermittently fed through the feed tube, the collet of the desired shape being formed from a metal blank such as a sheet steel blagnk, by form? ing or shaping that blank into a collet comprising a tubular or hollow body portion and a gripping portion, whereby the bore of the collet'i's formed without drilling the same from end to, end thereof and whereby the metal of the resilient fingers does not have to be of greater thickness than the metal of the body of the collet.

What we claim as our invention, and desire to secure by Letters Patent, is

1. A sheet-metal blank, for a feed collet,

consisting of a body part, and a plurality Y of tapered finger pieces extending rom one longitudinal edge of said body part, the outer terminal ortions of said finger pieces having approximately parallel lateral edges.

2. As an improved article of manufacture, a sheet-metal feed collet comprising a rolled up screw-threaded body and fingers, the latter being spaced from each other, and said body having abutting edges, and means to close the joint at such ed es.

3. A feed collet adapte for attachment to the end of a stock bar feed tube of a machine and comprising a sheet steel blank bent or shaped into a tubular body having a lengthwise extending non-drilled bore, and resilient spaced gripping portions adapted to grip the same bar of stock as it is intermittently fed through the feed tube and to 4. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a pressed sheet steel blank bent or shaped into a tubular body with the grain of the metal running lengthwise thereof, and with a lengthwise extending non-drilled bore, and having a gripping portion adapted to grip thesame bar of stock as it is intermittently fed through the feed tube.

5. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a sheet metal blankbent and held with the free edges in position to form a bore therethrough, said collet having a plurality of resilient gripping fingers effective to grip the same bar of stock as it is intermittently fed through the feed tube and to rotate with such stock bar.

6. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a sheet metal blank bent and held with the free edges in position to form a bore therethrough, said collet having a shouldered body and a plurality of spaced and resilient fingers terminating in gripping surfaces effective to grip the same stock bar as it is intermittently fed through the feed tube.

7. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a sheet metal blank bent with the contiguous edges in position to form a bore therethrough and having a plurality of resilient fingers terminating in gripping surfaces shaped to conform to the stock bar to be fed and effective to grip the same bar of stock as it is intermittently fed through the feed tube.

8. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a sheet metal blank bent or shaped into a tubular body with the opposite edges held in position to form a lengthwise extending bore, the body having stamped lengthwise projecting, tapered, spaced and resilient fingers forming a tapered bore and effective to grip the same bar of stock as it is intermittently fed through the feed tube and to rotate with said stock bar.

9. A feed collet adapted for attachment to the end ofa stock bar feed tube of a machine and comprising a sheet metal blank bent or shaped to have the contiguous'edges held in position to form a bore therethrough, said collet comprising a cylindrical body having a shouldered and threaded portion, and a plurality of projecting, resilient, spaced and tapered fingers extending from said body and having substantially a conical shape, said fingers terminating in elongated gripping surfaces shaped to conform to the shape of the stock bar to be fed and effective to grip the same bar of stock as it is intermittently fed through the feed tube.

10. A feed collet adapted for attachment to the end of a stock bar feed tube of a machine and comprising a sheet metal blank bent or shaped into a tubular body with the opposite edges held-in position to form a lengthwise extending bore, the body having means for seturing it to the end of the feed tube and also having a lengthwise projecting tapered, resilient fingers forming a tapered bore, the bore of the body having greater diameter than the major part of the bore of the fingers, and said fingers terminating in elongated gripping surfaces substantially parallel in the direction of their length, and having a bore of less diameter than the major part of the bore of the fingers and shaped to conform to the shape of the stock bar to be fed and efiective to grip the same .bar of stock as it is intermittently fed through the feed tube.

gripped and eifective to grip the bar of stock as it is intermittently fed through the feed tube and to rotate with such stock bar, said gripping surfaces having elongated inner walls substantially parallel in the direction of their length, said body having its oppo site end threaded for attachment to the end of the feed tube and said body having a shoulder adjacent to the inner end of the threads.

12; A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a sheet metal blank bent and held with the free edges in position to form a bore therethrough, said collet having a plurality of resilient gripping fingers effective to grip J the same bar of stock as it is intermittently fed through the feed tube, the thickness of the metal/0f the fingers being no greater than that of the metal of the body of the collet.

13. A feed collet adapted for attachment to the end of a stock bar feed tube of a metal working machine and comprising a struck-up or stamped sheet metal blank bent or shaped to form a hollow body having at one end projecting spaced and resilient gripping means having gripping surfaces corresponding to the shape of the stock bar to be gripped and efl'ective to grip the bar of stock as it is intermittently fed through the feed tube and to rotate with such stock bar, said gripping surfaces having elongated inner walls substantially parallel in the direction of their length, the thickness of the metal of the gripping means being no greater than n that of the metal of the body, said body having its opposite end threaded for attachment to the end of the feed tube and said body having a shoulder adjacent to the inner end of the threads.

14. The method of making a feed collet,

which consists in first shaping a flat metal the blank into tubular form and securing the edges of the blank together.

15. The method of making a feed collet, which consists in first producing a flat metal blank having the density of both surfaces thereof substantially equal, then shaping the blank to form a body and a plurality of finger pieces, and then bending the blank into tubular form and binding the adjacent edges thereof together.

16. The method of making a feed collet, which consists in first shaping a flat metal blank to form a body and a plurality of projecting tapered finger pieces, then bending the blank into tubular form and joining-the contiguous edges thereof. 1

17. The method of making a feed collet, which consists in stamping a fiat metal blank to form a body and finger pieces, then bending the blank into a tube, then securing the edges together, and then pressing the finger pieces toward' the center. i

18. The method of making a feed collet, which consists in stamping a flat metal blank to form a body and finger pieces, then bending the blank into a tube, then securing the edges together, then pressing the finger pieces toward the center and simultaneously pressing the free ends of said finger pieces into a form to conform to the shape of the stock to be fed, as for instance square, oval,

or hexagon.

19. The method of making a feed collet,

which consists in first forming from a sheet which consists in stamping a fiat metal blank to form a body and tapered finger pieces, then bending the blank into a tube, then securing the edges together, and then pressing the finger pieces toward the center.

21. The method of making a feed collet, which consists in stamping from a sheet of metal a blank having a body and tapered finger pieces, then forming the blank into substantially a cylinder with the finger pieces forming substantially a frustum of a cone and terminating in grippingsurfaces, then welding the adjacent edges of the blank together, then pressing the finger pieces toward the center and simultaneously pressing said fingers into a form to conform to the shape of the stock to be fed, and then threading a part of said body.

22. The method of making a feed collet, which consists in forming the same from a metal blank having a resilient finger, and then securing the edges of the blank together, said finger being pressed to form an elongated gripping surface.

23. The method of making a feed collet, which consists in bending a Hat blank into a cylinder with the free edges held in juxtaposition, said cylinder-comprising a body 7 portion and a plurality of projecting resilient fingers, said fingers being pressed to form an elongated gripping surface.

24. The method of making a feed collet, which consists in bending a flat blank into a cylinder with the free edges held in juxtaposition, said cylinder comprising a threaded body portion and a plurality of projecting tapered resilient fingers, said fingers being pressed to form an elongated gripping surface.

CHARLES J. FANCHER. ROBERT A. JOHNSON. Witnesses:

R. P. CHUnomLL, O. F. BENsoN. 

